N990UA

BOEING B-737 Serious injury Part 121 — UNITED AIRLINES, INC.

Operated by UNITED AIRLINES (per NTSB report)

ATA 5320

Part: STRINGER CLIP — DAMAGED (FUSELAGE) · airframe 58,964 hrs · 44,930 cycles

STRINGER CLIP DAMAGED, AT BS500B, STR1L. REPLACED STRINGER CLIP. MAJOR REPAIR ACCOMPLISHED.

ATA 5310

Part: DOOR FRAME — DAMAGED (FUSELAGE) · airframe 58,964 hrs · 44,930 cycles

FWD CARGO DOOR FRAME DAMAGED AT LOWER FORWARD CORNER. REPLACED FRAME. MAJOR REPAIR ACCOMPLISHED.

ATA 2930

Part: WARNING LIGHT — ILLUMINATED (HYD SYSTEM)

THE CREW REPORTED THE 'A' HYDRAULIC SYSTEM QUANTITY INDICATION OF 1.9 GALLONS ALONG WITH THE ILLUMINATION OF THE LOW QUANTITY LIGHT FOR THE STANDBY HYDRAULIC SYSTEM.

ATA 7200

Part: ENGINE — FAILED (NR 1)

NR 1 ENGINE EGT LIMIT EXCEEDED, HIGH OIL PRESSURE AND HIGH OIL TEMPERATURE. *S/D* THE THROTTLE LINKAGE BECAME DETACHED AND NORMAL ENGINE VIBRATION CAUSED THE THROTTLE TO ADVANCE ON ITS OWN. THE EGT LIMIT WAS EXCEEDED AND THE ENGINE WAS SHUT DOWN. THE ENGINE WAS CHANGED AND THE AIRCRAFT PUT BACK INTO SERVICE.

ATA 2780

Part: VALVE — FAILED (LE FLAP)

LOST A SYSTEM HYDRAULIC QUANTITY AND PRESSURE AFTER GEAR EXTENSION AND DURING FLAP OPERATION. *S/D* FOUND THE FLAP FLOW LIMITING VALVE LEAKING. THIS UNIT WAS LEAKING BECAUSE THE BODY SEPARATED INTERNALLY. THE UNIT CONTAINS A FLOW RING WHICH FAILED DUE TO FATIGUE. THE UNIT ALSO HAD SEVERE EROSION IN A METERING ORIFICE HOLE. THE VALVE WAS REPLACED PER MM 27-53-03, OPS CHECK OK.

ATA 7261

Part: OIL LINE — CRACKED (NR 2 ENGINE)

NUMBER TWO ENGINE HAD LOW OIL PRESSURE. *S/D* THE NR 6 BEARING OUTER INTERNAL OIL PRESSURE LINE HAD CRACKED AT THE BRAZE JOINT NEAR THE 'B' NUT CONNECTION, CAUSING THE OIL LOSS. THE LINE WAS REPLACED AND THE ENGINE WAS BASE CHECKED, RUN IN THE TEST CELL, AND MADE SERVICEABLE.

ATA 3233

Part: ACTUATOR LUG — BROKEN (RT MLG)

RT MLG ACTUATOR O/B ATTACH LUG WAS FOUND BROKEN IN HALF. THE HALF THAT WAS BROKEN OFF WAS IN TWO SECTIONS AND WAS FOUND TRAPPED IN A SEAL RETAINER IN THE LOWER TRAILING EDGE PANEL. THE ACTUATOR WAS RETAINED IN POSITION BY THE GEOMETRY OF THE WALKING BEAM. NO LANDING GEAR MALFUNCTIONS REPORTED. PARTS ARE UNDER FAILURE ANALYSIS. *S/D* MODE OF FAILURE WAS STRESS CORROSION CRACKING DUE TO STEADY HIGH TENSILE STRESS APPLIED IN A CORROSIVE ENVIRONMENT OVER A LONG PERIOD OF TIME. THE FOLLOWING WILL HELP ALLEVIATE THIS DISCREPANCY: APPLICATION OF PRIMER AND LOCKTITE TO BARE ALUMINUM SURFACES AND APPLICATION OF CORROSION INHIBITING SEALANT AROUND BEARING TO PREVENT MOISTURE INGRESS.

ATA 2822

Part: BOOST PUMPS — FAILED (NR 1 FUEL TANK)

AFTER TAKEOFF, NUMBER ONE ENGINE FORWARD AND AFT LOW PRESSURE LIGHTS ILLUMINATED. CIRCUIT BREAKERS WERE FOUND POPPED, RETURNED TO DEN. *S/D* REPLACED FWD AND AFT FUEL BOOST PUMPS, FUEL PANEL, FWD AND AFT CIRCUIT BREAKERS, BLED PUMP LOW PRESSURE SWITCHES, SUMPED NR 1 TANK AND FOUND NO CONTAMINATION, OPS CHECK GOOD.

ATA 2752

Part: INDICATOR — INOPERATIVE (COCKPIT)

FLAPS WOULD NOT EXTEND DURING APPROACH,TRIED MULTIPLE TIMES AND THEY FINALLY EXTENDED AFTER THE SIXTH TRY. AFTER LANDING FLAPS WOULD NOT RETRACT. *S/D* REPLACED TRAILING EDGE FLAP POSITION INDICATOR, CHECKED OK.

ATA 7603

Part: THROTTLE CRANK — LOOSE (NR 2 ENGINE)

CREW REPORTS NR 2 ENGINE WILL NOT REDUCE FROM CRUISE POWER SETTING WITH THROTTLE AT IDLE. ENGINE SHUTDOWN FOR LANDING AT SLC DUE TO NO RESPONSE FROM THROTTLE. FOUND THROTTLE CRANK ARM NUT AT CROSS SHAFT BACKED OFF. REINSTALLED THROTTLE CRANK ARM TO CROSS SHAFT, TORQUED AND SAFETIED. JOB CARDS ARE BEING REVISED TO CHECK THIS NUT.